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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Many AVX-512 functions take an int instead of unsigned int"
href="https://bugs.llvm.org/show_bug.cgi?id=45931">45931</a>
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<th>Summary</th>
<td>Many AVX-512 functions take an int instead of unsigned int
</td>
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>clang@evan.coeusgroup.com
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>There are a bunch of functions in AVX-512F which, according to Intel's
documentation (<a href="https://software.intel.com/sites/landingpage/IntrinsicsGuide/">https://software.intel.com/sites/landingpage/IntrinsicsGuide/</a>),
take an unsigned integer as an argument but clang's header has the type as a
signed integer.
This causes problems with -Wsign-conversion. Here is an example which will
generate a warning with -Wsign-conversion (or <a href="https://godbolt.org/z/kTBTAD">https://godbolt.org/z/kTBTAD</a> if
you prefer):
#include <immintrin.h>
static __m256i foo (__m256i a, unsigned int imm8) {
return _mm256_srai_epi64(a, imm8);
}
__m256i bar(__m256i a) {
return foo(a, 7);
}
AFAICT all the functions which take unsigned imm8 arguments have this problem
in clang. Here is a quick list:
* _mm256_mask_slli_epi16
* _mm256_mask_slli_epi32
* _mm256_mask_slli_epi64
* _mm256_mask_srai_epi16
* _mm256_mask_srai_epi32
* _mm256_mask_srai_epi64
* _mm256_mask_srli_epi32
* _mm256_mask_srli_epi64
* _mm256_maskz_slli_epi16
* _mm256_maskz_slli_epi32
* _mm256_maskz_slli_epi64
* _mm256_maskz_srai_epi16
* _mm256_maskz_srai_epi32
* _mm256_maskz_srai_epi64
* _mm256_maskz_srli_epi32
* _mm256_maskz_srli_epi64
* _mm256_srai_epi64
* _mm512_mask_slli_epi16
* _mm512_mask_slli_epi32
* _mm512_mask_slli_epi64
* _mm512_mask_srai_epi16
* _mm512_mask_srai_epi32
* _mm512_mask_srai_epi64
* _mm512_mask_srli_epi16
* _mm512_mask_srli_epi32
* _mm512_mask_srli_epi64
* _mm512_maskz_slli_epi16
* _mm512_maskz_slli_epi32
* _mm512_maskz_slli_epi64
* _mm512_maskz_srai_epi16
* _mm512_maskz_srai_epi32
* _mm512_maskz_srai_epi64
* _mm512_maskz_srli_epi32
* _mm512_maskz_srli_epi64
* _mm512_slli_epi16
* _mm512_slli_epi32
* _mm512_slli_epi64
* _mm512_srai_epi16
* _mm512_srai_epi32
* _mm512_srai_epi64
* _mm512_srli_epi16
* _mm512_srli_epi32
* _mm512_srli_epi64
* _mm_mask_slli_epi16
* _mm_mask_slli_epi32
* _mm_mask_slli_epi64
* _mm_mask_srai_epi16
* _mm_mask_srai_epi32
* _mm_mask_srai_epi64
* _mm_mask_srli_epi32
* _mm_mask_srli_epi64
* _mm_maskz_slli_epi16
* _mm_maskz_slli_epi32
* _mm_maskz_slli_epi64
* _mm_maskz_srai_epi16
* _mm_maskz_srai_epi32
* _mm_maskz_srai_epi64
* _mm_maskz_srli_epi32
* _mm_maskz_srli_epi64
It looks like GCC has the same problem, though ICC and MSVC do not.</pre>
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